rank the following compiunds in order of increasing boiling points.

a. CO
b. C2H6
c. NH3

What's your main problem with this. You do it with intermolecular forces, H bonding, molar mass, etc.

it is in order already right?

If you mean increasing boiling points from top to bottom, yes.

To determine the order of increasing boiling points for the given compounds (CO, C2H6, NH3), we need to consider the intermolecular forces between their molecules. These forces are influenced by factors such as polarity, molecular weight, and the presence of hydrogen bonding.

1. CO (Carbon Monoxide):
Carbon monoxide is a small nonpolar molecule. It experiences only London dispersion forces between its molecules. London dispersion forces are weak intermolecular forces that arise due to temporary fluctuations in electron distribution. As a result, CO has the lowest boiling point among the given compounds.

2. C2H6 (Ethane):
Ethane is a nonpolar molecule composed of two carbon atoms and six hydrogen atoms. Like CO, it also experiences London dispersion forces. However, its larger molecular size compared to CO leads to stronger London dispersion forces in C2H6. Therefore, ethane has a higher boiling point than carbon monoxide.

3. NH3 (Ammonia):
Ammonia is a polar molecule due to the unequal sharing of electrons between nitrogen and hydrogen. It experiences dipole-dipole interactions between its molecules. Dipole-dipole forces are stronger than London dispersion forces, resulting in a higher boiling point for NH3 compared to both CO and C2H6.

Therefore, the increasing order of boiling points for the given compounds is: CO < C2H6 < NH3.